Safety device for steam-boilers and other fixtures containing steam under pressure.



A. L. BRIDGHAM.

SAFETY DEVICE FOR STEAM BOILERS AND OTHER FIXTURES CONTAINING STEAM UNDER PRESSURE.

APPLICATION FILED APR. 13, 1915.

1 ,Q2@,9%4. l Patented Mar. 27, 1917.

' 2 SHEETS-SHEET 1.

rm: lvmmls PETERS m, PMOm-Lrrum. WASH ma muI n. c.

, A. L. BRIDGHAM. SAFETY DEVICE FOR STEAM BOILERS AND OTHER FIXTURES CONTAINING STEAM UNDER PRESSURE.

APPLICATIOWFILED APR. 13, 1915-,

Patented Mar. 27, 1917.

1 r1 k mmms P5 12:15 ca, Mowuma, wasmm? ran, a c.

llTl-ED PAT CFFTCE.

ARTHUR, L. BRIDGHAM, OF BOSTON, MASSACHUSETTS, ASSIGNOB OF ONE-HALF T0 CHARLES H. SHERBURNE, 0F BQETON, MASSACHUSETTS.

SAFETY DEVICE FOR STEAM-BOILERS AND OTHER FIXTURES CONTAINING STEAM UNDER, PRESSURE.

Application filed April 13, 1915.

To all whom it may concern:

Be it known that I, ARTHUR L. BRIDGHAM, of Boston, the county of Suffolk and State of Massachusetts, a citizen of the United States, have invented a new and useful Improvement in Safety Devices for Steam- Bcilers and other Fixtures Containing Steam Under Pressure, of which the following is a full, clear, and exact description, referencebeing had to the accompanying drawina's, forming a part of this specification, in explaining its nature.

The present invention relates to a safety device for; steam boilers and other fixtures containing steam under pressure by which the steam may be automatically shut off in case a break occurs in any of the connections through which the steam is being conveyed from the boiler or fixture. The device is especially adapted for steam boilers of locomotives or other fixtures connecting therewith contain ng steam under pressure where a device of this kind is of the utmost importance owing to the fact that the steam from the boiler is first directed into the cab of the locomotive or point adjacent thereto where it is distributed to various points of use. There is always great danger of the connections breaking, loosing steam within the cab and serious accidents have occurred on this account.

The object of my invention is to provide a safety device by which the steam may be automatically shut off in the event of such break, or, in fact, any break within the connections through which the steam is being conveyed which will unduly accelerate the flow or discharge of steam from the boiler. .-t is my object, also, to provide a safety device not dependent upon the operation of springs or other movable parts likely to get out of order, and one, also, which is entirely controlled by the steam pressure.

iv invention can best be seen and understood by reference to the drawings in which I have shown it applied to such portion of a locomotive boiler and associated parts as are necessary to a proper understanding.

In the drawings Figure 1 represents the device in side elevation, that portion of the boiler shown and other associated parts being illustrated partly in plan and partly in section.

Patented Mar. 27, 1917.

Serial No. 21,157.

Fig. 2 is a vertical section of the essential parts of the device.

Referring to the drawings 1 1 represents a portion of the shell of the boiler, 2 the steam dome, 3 the outlet pipe by way of which the steam is directed out of the dome. 4iis the fountain usually located within the cab and with which the outlet pipe connects and from which the steam is distributed in the usual manner.

The steam is directed into the outlet pipe from the chamber of the dome and otherwise controlled as follows: Connecting Within the dome with the outletpipe is an elbow 5. This elbow forms practically a part of the outlet pipe in extension of it. Secured to the inner end of this elbow is a pipe con nection 6 comprising also a valve casing. This casing is provided at its opposite ends with short tubular extensions 7 and 8, respectively, each exteriorly threaded. The end of the tubular extension 7 butts against the end of the elbow and connection is secured. to the elbow by means of a clamping nut 9 which screws onto the extension 7 and has bearing against an annular shoulder 10 formed on the elbow. A packing 11 is interposed between the elbow and connection forming a tight joint upon the tightening of the nut. At the opposite end of the connection 6 its exterior extension 8 projects through an opening in the side wall Of the dome and has threaded connection with that portion of the wall lining this opening. The extension 8 projects beyond the side wall of the dome, and threaded upon the projecting end thereof is a locking nut 12.

The casing 6 provides on the interior a valve chamber 13 with ports 14 on opposite sides thereof and a port 15 at the fore end. l/Vith the ports thus arranged steam will enter from the chamber of the dome into the valve chamber and thence flow through the port 15 into and through the elbow and outlet pipe. Lining the entrance to the port 15 is a valve seat 16. Contained within the easing 6 and movable therein to occupy open and closed position with relation to the valve seat 16 is a valve 18. 19 represents the stem of this valve or that by which the valve is supported and also manually controlled by a hand wheel 20 on the end of the stem, as will later be explained. The stem is threaded to turn in and out of a bonnet 22 located outside the dome and having threaded connection with the extension 8 of the valve casing. The joint between the stem and the bonnet is closed by packing 23 held compressed by a gland 24.

The stem 19 is a hollow stem, the passage 25 through it' connecting at the outer end of the stem with the atmosphere. At the inner end the stem is provided with a chambered extension 26 the end of which is closed by a plug 27. i

The valve 18 loosely connects with the stem 19 by means of a short auxiliary stem which connects directly with the rear side of the valve and extends therefrom through the plug 27 and into the interior of the chambered extension 26 of the main valve stem Where the stem 30 is provided with a head 31. This head is movable within the interior of the extension 26 between the plug 27 at its inner end and its outer end 32, forming a stop.

With the parts'thus arranged, the valve 18 is movable independently of the stem 26 a distance commensurate with the movement of the head 31 between the limits above defined, and this distance should be such as will permit of an independent movement of the valve from any openposition thereof, which is defined by the engagement of the head 31 with the stop 32, to its closed position, which is defined by the valve seat.

Assuming the valve to be. open, it may be closed manually simply by turning in the valve stem when the part 32 thereof will bear against the head 31 and thereby through the stem 30 force the valve to a closed position. When closed the valve may be opened manually simply by a reverse operation or by turning the valve stem outwardly until the plug 27 draws against the head 31 when, as the turning of the valve stem is continued, the valvewill be drawn to any desired open position.

Referring now to the automatic action of the valve, attention is first directed to the fact that the valve is located in the path of the steam as it flows from the chamber of the dome and interior of the valve casing through the port controlled by the valve and into the outlet pipe. The valve is accordingly subjected to the steam pressure on both the front and rear sides thereof, excepting, however, that the application of the steam pressure to the rear side of the valve tion. A further prearrangement of the valve resides in the fact that it is not only arranged in the path of the steam entering the outlet pipe, but it also occupies a position when open where it is susceptible to variations in pressure that may occur in the outlet pipe and which will depend upon the velocity of flow of the steam therethrough. The faster the flow, the less the pressure. The valve is accordingly set in an open position so close to its valve seat that when the steam has a usual normal flow through the port controlled by the valve and outlet pipe any reduction in pressure therein incident to such flow will have no effect upon the valve and it will be maintained by the pressure in its overbalanced open position as above described. The disposition of the valve is, however, such that when the flow of steam through the outlet pipe becomes unduly accelerated or undue drop of pressure develops therein, as for example by a break in the steam connections beyond the pipe, then the resulting drop in pressure within the pipe extends, owing to the proximity of the valve, to the face thereof and accordingly greater pressure will be exerted upon the rear side of the valve than upon its face, with the effect that the valve will be automatically and instantly closed. While it is pressure back of the valve which tends to close it when the pressure on the front side suddenly drops upon undue acceleration in the flow of the steam, yet the moving force exerted by the steam during the accelerated flow thereof may have some influence to close the valve.

To obtain the automatic closure it is of course necessary that the valve be accurately set and such setting may be obtained by the manual control and preferably by moving the valve forward from a full open position until it becomes susceptible to the influence above referred to.

Vhen the valve is closed it will of course be held closed by the pressure of the steam within the dome and under such circumstances it would be very ditlicult to open it by hand. Provision accordingly is made whereby the valve may be opened by the steam pressure.

Connecting with the boiler is a pipe 35 which extends upwardly to connect with the fountain. The passage through this pipe is controlled by a valve 36. When the' valve 18 is closed then upon closing all the connections leading from the fountain steam may be admitted from the boiler into the fountain and thence into the outlet pipe through the pipe 35 upon opening the valve controlling the passage through this pipe. Thereupon a pressure of steam may be obtained in the outlet pipe substantially equal to that in the boiler, with the eifect that the valve 18 will be opened by the pressure, which accordingly is greater upon the forward side 1,220,944 I iii;

of the valve than upon the reverse side thereof. While dependence is made upon the automatic closure of the valve 18 for shutting off the steam, yet the valve may be manually closed at any time as may be desired. When the device is applied to a locomotive boiler the wheel controlling the stem of the valve is easily accessible.

In further connection with the operation of the valve, it will be observed that the steam pressure within the dome 0r boiler is excluded at all times, both during the open and closed positions of the valve, from the passage extending through the stem and connecting with the atmosphere. The fact, also, that the steam is excluded from said passage during the closed position of the valve and the valve at that time is subjected to atmospheric pressure on the rear side thereof, permits of the valve being opened upon the admission of steam from the boiler to the outlet pipe, as above explained.

While I have described the safety device in its application to the steam boiler of a locomotive it will be understood of course that it may be used in connection with other types of fixtures containing steam under pressure.

It will also be understood that the specific embodiment of my invention shown may be changed in various details without departmg from the essence thereof.

Having thus fully described my inven-- tion, I claim and desire to secure by Letters Patent of the United States 1. In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, said valve being arranged whereby it may be subjected to the steam pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof so that the valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position Where it is subjected to and moved by the steam pressure to a closed position for closing said outlet pipe upon undue drop in pressure in the said pipe, meanshaving a passage 1n it through which atmospheric pressure may be directed to said valve by which it may be subjected to atmospheric pressure as aforesaid, and other means assisting in the con- -trol of said valve by which the pressure within said fixture is closed from said pas: sage connecting with the atmosphere at all times during both the open and closed posltions of said valve.

2. In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, said valve being arranged whereby it may be subjected to the steam pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof so that the valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position where it is subjected to and moved by the steam pressure to a closed position for closing said outlet pipe upon undue drop in pressure within said pipe, means having a passage within it through which atmospheric pressure may be directed to said valve, other means assisting in the manual control of said valve and permitting of the valve being moved to a closed position when open, said other means being adapted also whereby the valve may be made susceptible to said atmospheric pressure and whereby, also, the steam within said fixture may be excluded from said passage at all times both during the open and closed positions of the valve.

3. In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, said valve being arranged Whereby it may be subjected to the steam pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof so that the valve may be overbalanced and maintain-ed by the steam pressure in a normal open position but in a position where it is subjected to and moved by the steam pressure to a closed position for closing said outlet pipe by undue drop in pressure within said pipe, a valve stem having a passage through it by which atmospheric pressure may be directed to said valve, means whereby said valve may be connected to said stem to be manually controlled by it and said valve be movable to a closed position when open independently of said stem, said means being adapted also whereby the valve may be subjected to the atmospheric pressure acting through said stem, and the steam pressure within said fixture be excluded from the passage through the stem at all times both during the open and closed positions of the valve.

4. In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, said valve being arranged whereby it may be subjected to the steam pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof so that the valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position where it is subjected to and moved by the steam pressure to a closed position for closing said outlet pipe upon undue drop in pressure in the said pipe, a valve stem by which said valve may be manually controlled from outside the fixture, said stem having a passage through i it communicating with the atmosphere, a

Y mounting within which said stem is movable longitudinally, means carried by the valve independent of said stem and comprising a member under the influence of the atmospheric pressure acting through said passage within the stem, and means carried by said stem adapted to have contact with said member for assisting in the manual control of said valve, said last-named means being adapted, also, whereby the steam pressure within said fixture may be excluded from the passage through said stem at all times both during the open and closed positions of the valve.

5, In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, said valve being arranged whereby it may be subjected to the steam .pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressureon the other side thereof so that the valve may be overbalanced and maintained iary valve stem extending from the rear side of said valve through the end of said extension or chamber thereof, and a head carried by said auxiliary stem and contained within the chamber of said extension.

6. In a safety device for steam boilers of locomotives, the combination with the steam dome of the locomotive and steam outlet pipe leading from within the chamber of said dome, of a valve casing interposed between the end of said pipe and the wall of said dome and having formed within it a valve seat at the entrance to said pipe, a

valve contained within said casing and ar-- ranged whereby it may be subjected to the steam pressure within said dome on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof whereby said valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position where itis susceptible to and may be actuated and moved by the steam pressure to a closed position against said valve seat for closing said outlet pipe upon undue drop in pressure within said pipe, and means for mounting and otherwise assisting in the control of said valve whereby it may be manually controlled from without said dome to have the aforesaid normal open position during the normal flow of steam through said pipe and be automatically closed by the steam pressure within the dome upon undue drop in pressure within said pipe as aforesaid.

7. In a safety device for steam boilers of locomotives, the combination with the steam dome of the locomotive and steam outlet pipe leading from within the chamber of said dome, of a valve casing interposed between the end of said pipe and the wall of said dome and having formed within it a valve seat at the entrance to said pipe, a valve contained within said casing and arranged whereby it may be subjected to the steam pressure within said dome on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof whereby said valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position where it is susceptible to and may be actuated and moved by the steam pressure to a closed position against said mlve seat for closing said outlet pipe upon undue drop in pressure within said pipe, a valve stem by which said valve may be manually controlled from outside the dome, said stem having a passage through it communicating with the atmosphere, a fixture within which said stem is movable longitudinally, means carried by the valve independent of said stem and comprising a member under the influence of the atmospheric pressure acting through said passage within the stem, and means carried by said stem adapted to have contact with said member for assisting in the manual control of said valve, said lastnamed means being adapted, also, whereby the steam pressure within said dome may be excluded from the passage through said stem at all times both during the open and closed positions of the valve.

8. In a safety device of the type specified, the combination with a fixture containing steam under pressure and steam outlet pipe leading therefrom, of a valve controlling said pipe, means for supporting and arranging said valve whereby it may be subjected to the steam pressure within said fixture on one side thereof and to both said steam pressure and atmospheric pressure on the other side thereof so that the valve may be overbalanced and maintained by the steam pressure in a normal open position but in a position where it is subjected to and moved by the steam pressure to a closed position for closing said outlet pipe upon undue drop in pressure in said pipe, means whereby said valve may be subjected at all times, both during the open and closed positions thereof, to the atmospheric pressure, and means whereby steam under pressure substantially equal to that obtained within said fixture may be directed into and chambered within said outlet pipe when said valve is occupying a closed position for opening the same.

9. In a safety device for steam boilers of locomotives, the combination with the steam dome of the locomotive and steam outlet pipe leading from within the chamber of the dome of a valve casing interposed between the end of said pipe and the wall of said dome to have threaded connection with said dome around an opening therein, and having formed within it a valve seat at the entrance to said pipe, a valve within said casing, means for supporting said valve whereby it may be applied to or removed from said casing independently of the casing, said means comprising in part a bonnet having threaded connection with said casing.

ARTHUR L. BRIDGHAM.

Witnesses:

Jornv E. R. HAYES, M. E. FLAHERTY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

